Many network devices communicate with other devices in a network through optical signals via fiber-optic cables. The data in such networks may be at risk of unwanted access through tampering and/or tapping of the fiber-optic cables. To combat such tampering and/or tapping, systems exist that use additional fiber to detect movement of the cable, or insert a tap into the cable to measure power attenuation. However, these systems are expensive and require extra equipments to perform the monitoring tasks.